Process for lining shafts



y 1952 c. SONDEREGGER PROCESS FOR LINING SHAFTS Filed Dec. 24, 1947 Fig.1v

INVENTOR;

[ar/ Sonclere er A-r-ron-wegs Patented July 8, 1952 rRocE's's Foa LINING SHAFTS' g Carl SondereggCr; Zurich; Switzerland, assignor t Electro Watt Electrical and Industrial Managerhent .00., L'tdi, Zurich, Switzerland, a com- "1 panyorswitzeriana ApiilicationDecember 24, 1947, Serial No; 793,?02'

In? Switzerland December 21, 19 M) Section" 1, Public Law 690, August 8, 1946 Patentexpires December 21, 1966 Pressure shaftsa're generally 'made nowadaysby introducin sectionswf' Piping fixed length into excavated shaffiand joined together.- After-being placed in position these lengths'-or section's'of steel-{piping are backed with concrete to give them a -bearing on therock; The =pipes must'be of such di'rnension's that' they withstand any pressure lik'ely w pe exerted eitherfrom inside or outside; and 'threfore have walls of substantial thickness?" Quit---apart from the complications-"involved m ning of the extremely heavy lengths of pip'ing, this methodof construction is also eii-tr'emely eapsnsive and the backin'g' witl'i conc'rteis a diffi'cult process;

The present 'inyentiori relates' to 'a process for the pro'ductidnof pressure shafts with which process omy armourmg-"or minimumwall-thicb ness is necessary; which-process is considerably simpler and cheaper-' than the' -m'ethod of construction described above; rt ess; for the pressure 1' shaft lil'lf.

haracterized' 'by he which the inner concretelining canwithstand,

in order to ensure snug fitting of the sheet.

The pressure shaft produced by this process is characteriz'edbyen 'outer'layer' of concrete bearing againstthe rock, 'a 'furthef, inner concrete lining and a thin sheet armouring between these layers of concrete, the sheetarmouring lying directly on the inner concrete liningr whilst between the sheet armouring and the outerlayer of concrete a subsequently applied thin layer of concrete, is provided.

The sheet armouring, which is roughly 2 mm.-

I concretefis applied armouringfconsisting (Cl. til-41) tOgethe'rby filIet welding. The strength'of the welded 'g'loin'tscanthereby be made t'o equa'l that of the sheet; For'transverse sections, however,

it is suficient' ii" fillet welding is carried Tout over 5 the thicknessfof the sheet; 1 v I v 7 It is-"pos sible' however, to dispense withwelding the individual lengths" together" by makin boththe longitudinal and-L transverse sections overlappingand inserting a wire meshfbetween 10 the overiappin'g parts; By selecting'the amount of overlap the ce'me'nt" grout "penetrating intothe overlap can be"made' to"take'the" full strain' b'f" the sheet after the cement has set hardi Be-'- tween the sheet 'arm0uring" and the outer'ce'ment ring a space must be' -le'ft,'5 asalr'a'dy 'stated; this"* space being thenfilledwith cementgroutjintro duced" under 1 pressure." This cavity can 'bepro duced by fastening as'pot-welded wire mesh' tothe outer layer ofconcretebefore the 's heet sec-' tions are introduced. 'Ihis-w'ire mesh ensures that a space is left between the sheet ar'rnduring and the outer layer of concrete and enables' the cement grout introducedunder pressure com pletelyto" ifill 'the intermediate space; Alter natively,'ribsor grooves may beprovidedon'th'e; outer concrete" layer at the tim'e' said'layeris produced, though these would have to be fash' ioned in such'a way as to enable the'cem'erlt grout to penetrateintever'y direction. Inview" -of the fact thatthe'. cement grout'is injected under high pressure the sheet jacket will 'cer-' tainly'be moved slightly, sothat an intermediate layer, thin though it c the injected cement: grout;

In" the enclosed "drawing Figs: 1-4 show'several typical embodiments of'the invention; and-rep resent Fig: 1 a section shcwingrthe structure "of the 40 press'ure' shaft;

Fig.1: 2*thejoining: of the ammal sections ofthe individual pipes;

Fig." 3 the joining ofther. lengths of; piping-by the insertion of a wire mesh;

Fig. 4 a section of the structure of a pressure shaft, ribs being provided, on the outer ring of concrete, between said outer ring of concrete and the sheet armouring.

In Fig. 1, l designates the rock face of the excavated shaft on which rock face a layer of concrete 2 is first laid. A wire mesh 3 is secured to this layer of concrete, after which the sheet metal jacket 4 is placed in position. Said sheet metal jacket is joined, as shown in Fig. 2, by a fillet welding 5, plates 6 and I, which are con- ENT OFFICE maybe; can be'produced, even at those points where'ribs are providedyby' a a 3 siderably thicker than the sheet metal jacket 4 itself, being welded to the sheet metal jacket 4, which is only about 2 mm. thick. In this way it is possible to arrange for the strength of the welded joint to be equal to that of the sheet metal jacket. After the sheet metal jacket 4 has been placed in position, a further layer of concrete 8 is applied, which may for example be reinforced with iron 9. Cement grout is injected between the sheet metal jacket 4 and the layer of concrete 2 under the highest pressure that the layer of concrete 8 is capable of withstanding, whereby the sheet metal jacket 4 is pressed against the inner ring of concrete and an intimate union between all the layers is created. In the case of the embodiment according to Fig. 3 a wire mesh 3 is inserted in the overlap of the individual sections. In the course of filling up the space between the layer of concrete 2 and the sheet metal jacket 4 of the cement grout will also penetrate into the overlap of the pipe section and, after the cement has set, form a joint. The overlap can be of such dimensions that the strength of the joint is, with absolute certainty, equal to that of the sheet metal armouring.

Finally Fig. 4 shows how, instead of the wire mesh 3, grooves l are provided on the outer layer of concrete 2. As already mentioned, the high pressure under which the cement grout is injected will tend to move the sheet metal jacket 4 slightly, so that a layer of cement is formed even underneath the bearing surfaces between the grooves.

As has been shown by the above explanation, it is possible with the process according to the invention to make, with extremely simple means and at low cost, pressure shafts which are absolutely tight and are at the same time capable of withstanding all pressures which may arise either from inside or outside.

I claim:

1. A process for making armoured pressure shaft linings comprising the steps of applying an outer layer of concrete to the shaft, placing an armouring member of thin sheet metal and overlapping longitudinal edges in spaced relationship with the outer layer of concrete, securing together the overlapping edges of the armouring member, applying an inner layer of concrete to the inner surface of the armouring member, and filling the space between the outer layer of concrete and the armouring member with cement grout under pressure limited by the strength of the inner concrete layer.

2. A process for making armoured pressure shaft linings comprising the steps of applying an outer layer of concrete to the surface of the shaft, placing a wire mesh against the surface of the outer concrete layer, placing one imperforate armouring member with overlapping longitudinal edges and open ends in the shaft and adjacent the wire mesh, placing another imperforate armouring member WithOverlapping longitudinal 4 edges and open ends in the shaft with one end in abutted relationship with an end of the first armouring member, securing together the overlappinglongitudinal edges; of each member, placing reinforcementmemb'ers adjacent the inner surface of each member, applying an inner layer ofconcrete 'over the reinforcement members and against the inner surfaces of the armouring members, and introducing cement grout under pressure into the space occupied by the wire mesh.

3. A process for making armoured pressure shaft linings comprising the steps of applying an outer concrete layer to the shaft, placing an armouring member of thin sheet metal and overlapping longitudinal edges and open ends in the shaft adjacent the outer concretelayer, placing a second armouring member of thin sheet metal and overlapping longitudinal edges and open ends in the shaft adjacent the outer concrete layer with one end of the second member overlapping the corresponding end of the first member, securing together the overlapping portions .of the members, applying an inner layer of reinforced concrete to the inner surface of the armouring members, and introducing cement grout under a pressure of less than the fracturing pressure of the inner concrete .layerintermediate the outer v concrete layer and the armouring members.

4. A process for making armoured pressure shaft linings comprising the steps of applying an outer concrete layer to the shaft, forming inter-, connecting grooves on vthe surface of the outer concrete layer, placing an armouring member of thin sheet metal' and overlapping longitudinal edges and open ends inthe shaft against the outer concrete layer, placing a second-armouring member of thin sheet metaland overlapping longitudinal edges andopen ends in the shaft against the concrete layer with one end of the second member overlapping the corresponding end of the first member, placing a wire -.mesh between the overlappingedges of each member, placing an inner layer of reinforced concrete against the inner surface of the armour-ing member, and introducing cement grout under a pressure less thanthe fracturing pressure for the inner reinforced concrete layer intermediate the outer concrete layer and armouring members.

CARL SONDEREGGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,208,302 Fernandez July 16, 1940 FOREIGN PATENTS Number Country Date 427,473 Great Britain 1925 511,080 Great Britain 1935 

